Loud-speaker



June 3, 19 30. C COOK 1,762,050

LOUD SPEAKER Filed Auga 24; 1928 WITNESSES 0 ENTOR k harles .000 4 .9%,, BY 9 I ATTORNEY Patented June 3, 1930 PATENT OFFICE CHARLES G. COOK, OF PORTSMOUTH, NEW HAMPSHIRE LOUD-SPEAKER Application filed August 24, 1928.

This invention relates to loud speakers.

It is an object of the invention to provide a novel and improved loud speaker in which a single diaphragm is adapted to propagate sound waves from a plurality of tone chambers.

Another object of the invention is to provide improved actuating means for a sound propagating diaphragm.

Another object of the invention is to provide a bell crank actuating means which is adapted to cause vibrations from the sound propagating diaphragm in response to applied vibrations from an electromagnetic actuating unit.

Numerous other objects and features of the present invention will be apparent from a consideration of the following specification taken in connection with the drawing in which there is disclosed a longitudinal vertical section of one form of my present invention.

Referring more particularly to the drawings, there is provided a base upon which is vertically mounted an internally threaded casing 11 within which a sound propagating diaphragm 12 is positioned and secured for vibration between a pair of threaded gaskets 14. It may be readily seen by this 30 construction that threaded adjustments of the gaskets 14 may be resorted to for controlling the tension applied to the diaphragm l2 and for the removal and insertion of the diaphragm.

Communicating with either side of the easing 11 shells 15 are provided which include oppositely extending members 16 to which air column horns or open ended resonance chambers 17 are secured. Thus, it may be seen that there is provided on either side of the diaphragm 12 tone chambers associated with air column horns. It may be readily seen that the position of the diaphragm within the casing 11 will determine the size of the resonating chamber, and thus determine the musical frequency to which it is responsive. It is also understood that if desired the horns 17 may be constructed in a manner whereby their natural frequencies differ, and thus the propagation of sound. waves from til Serial No. 301,901.

the opposite side of the diaphragm 12 will be of different character.

For actuating the diaphragm 12, an actuating arm 18 is provided, one end of which is secured to the diaphragm 12 as at 19 in any desired manner. The opposite end is adapted for actuation by vibration of a bell crank 20, the vertical end of which is secured to the arm 18 as at 21, and its center portion being supported for rotation upon a vertical support 22 carried by the base 10. The horizontal arm 23 of the bell crank 20 is adapted to be positioned adjacent a pole 24: of a suitable electromagnetic actuating unit 25 which is adapted for actuation in response to electrical impulses of sound frequency impressed thereon through the medium of conductors 26 which may lead from any desired source of energy such as an amplifying unit ordetecting system.

In the operation of the device it may be readily seen that electrical impulses impressed upon the electromagnetic unit 25 result in corresponding vibrations of the arm 23 of the bell crank 20, which, by pivotal movement with respect to its support 22 and through the connection as at 21 with the arm 18, causes corresponding vibration of the arm 18, and thus, vibrations of the diaphragm 12 by virtue of the connection of the arm 18 with the diaphragm as at 19. As previously described, it will be understood that the vibrations of the diaphragm 12 result in periodic compressions and rarifications of the atmospheric medium within the tone chamber and horns, and thus propagate sound waves in the surrounding atmospheric medium, such sound Waves being propagated in the opposite direction by the opposite sides of the diaphragm, and if desired, resonance and amplification effects may be imposed upon the oppositely directed sound waves by varying the character of the horns and the position of the diaphragm within the casing 11.

Thus, it may be readily seen that my invention provides a new and improved loud speaker adapted for use in connection with radios or similar electrical impulse-transmitting apparatus, the structure being such as to provide for the opposite production of QTY sound Waves in response to vibrations of the diaphragm which is actuated through the medium of an improved bell crank vibration translating system.

It is to be understood that the form of the invention herein disclosed is only one of a plurality of structures which may embody my invention, and that modifications and alterations, and the full use of equivalents may be resorted to Without departing from the spirit or scope of the appended claims.

I claim:

1. In a device of the character described, a central cylindrical casing, a diaphragm mounted Within said casing, tone chamber forming members mounted on the opposite ends of said casing, including tubular me1nbers, sound propagating horns associated with said members, and actuating means for said diaphragm extending through one of said members.

2. In a device of the character described, a central cylindrical internally threaded casing, a diaphragm mounted Within said casing, externally threaded means Within said casing for retaining said diaphragm, tone chamber fori'ning members mounted on the opposite ends of said casing, including tubular members, sound propagating horns associated With said members, and bell-crank actuating means for said diaphragm extending through one of said members.

3. In a device of the character described, a central cylindrical internally threaded casing, a diaphragm mounted Within said casing, externally threaded means Within said casing for retaining said diaphragm, tone chamber forming members mounted on the opposite ends of said casing, including tubular members, sound propagating horns associated with said members, and bellcrank actuating means for said diaphragm extending through one of said members, said means including an extending arm pivotally associated With said diaphragm, its free end apertured to receive therethrough one arm of said bell crank.

CHARLES G. COOK. 

